Lymphocystis viruses induce giant cells in the skin of various fishes. Walleye cells respond differently in pattern, rate of growth, and size limit to virus from walleye and from bluegill. So far, walleye virus has not infected bluegill, but further attempts are being made with fingerling bluegills (more susceptible?), and with various physiological stresses, or with viruses pretreated to modify their coats. Older lymphocystis giant cells show more abnormal virus structure: giant virions, or virions with off-angles, or defects in one or other coat layer. Attempts are being made to correlate these abnormalities with the results of uncoating treatments. A further attempt will be made to superinfect lymphocystis cells with one of the available walleye C-type viruses: from sarcoma, or from epidermal hyperplasia. Though these two C-type viruses have not been successfully introduced into normal bluegill tissues, this attempt is justified by a former chance finding by electron microscopy of a C-type superinfection in bluegill lymphocystis cells. Minor projects include: Electron microscopy of a clam gill nodule, including virus-like particles; and possibly EM of a recently found metastasizing clam tumor (in collaboration with M. M. Barry). Study of cytopathological reaction to fungus cysts in newts.